J/A+A/708/A321 MeerKAT radio emission search from magnetars (Bause+, 2026)
Searching for radio emission from radio quiet magnetars with MeerKAT.
Bause M.L., Kaur K., Rammala-Zitha I., Spitler L.G.
<Astron. Astrophys. 708, A321 (2026)>
=2026A&A...708A.321B 2026A&A...708A.321B (SIMBAD/NED BibCode)
ADC_Keywords: Stars, neutron ; Radio sources
Keywords: stars: magnetars - stars: neutron
Abstract:
Magnetars are neutron stars that occupy the extreme end of the neutron
star population, with magnetic field strengths of more than 1012G.
They have been proposed as one of the most likely progenitor models
for the phenomenon of energetic, ms-duration, extragalactic radio
bursts (FRBs), which have been increased even further due to the
FRB-like bursts emitted from the galactic Magnetar SGR 1935+2154.
However, only a low fraction of the magnetars (six in total) have been
detected in the radio regime and thus most magnetars are radio quiet.
We conducted regular observations of 13 radio quiet magnetars to probe
the long-term radio quietness using the most sensitive telescope in
the southern hemisphere: MeerKAT. These observations provide deep
constraints on the radio emission of magnetars, relevant for the
progenitor models of FRBs
Given that MeerKAT is an interferometer, we probe the magnetars for
radio emission in both imaging and time domain. We search in the time
domain in a DM range of 20pc/cm3 to 10000pc/cm3 for single pulses
using a TransientX-based search pipeline (the FRB perspective) as well
as from a pulsar perspective by folding the data using the X-ray
ephemeris. On the other hand, we use the imaging domain to search for
persistent radio emission in total intensity and circular
polarisation, as well as to create light curves using snapshot
imaging, having the long transient perspective as well.
We find no radio emission in the time domain for any of the observed
magnetars. Nevertheless, we are providing deep limits of the mean flux
density (52uJy to 68uJy) and the single pulse fluence 39mJy.ms to
52mJy.ms. From the image domain, we provide individual upper limits
on the persistent radio emission and the light curve for the 13
magnetars. Additionally, an ultra-long period transient and an
additional magnetar happened to be in the imaging beam for which be
provide lower limits as well.
We provide an extensive series of deep upper limits in the time
domain, but also as a novelty limits from the imaging domain for the
magnetars. As the current magnetar radio emission models are based on
a few radio loud magnetars, we encourage monitoring of radio quiet
magnetars independent of their X-ray flux with high cadence for
further insights into their potential for emitting in the radio
regime.
Description:
These are the total intensity images of the sources observed during
the last two epochs of this project.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
list.dat 148 18 List of fits images
fits/* . 18 Individual fits images
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Byte-by-byte Description of file: list.dat
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Bytes Format Units Label Explanations
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1- 21 A21 --- Name Star name
23- 31 F9.5 deg RAdeg Right Ascension of center (J2000)
32- 40 F9.5 deg DEdeg Declination of center (J2000)
42- 46 I5 --- Nx Number of pixels along X-axis
48- 52 I5 --- Ny Number of pixels along Y-axis
54- 74 A21 "datime" Obs.date Observation date
76- 82 F7.5 GHz Freq Observed frequency
84- 89 I6 Kibyte size Size of FITS file
91-112 A22 --- FileName Name of FITS file, in subdirectory fits
114-148 A35 --- Title Title of the FITS file
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Acknowledgements:
From Marlon L. Bause, mbause(at)mpifr-bonn.mpg.de
The MeerKAT telescope is operated by the South African Radio Astronomy
Observatory, which is a facility of the National Research Foundation,
an agency of the Department of Science and Innovation. This work has
made use of the "MPIfR S-band receiver system" designed,
constructed, and maintained by funding of the MPI fur Radioastronomy
and the Max Planck Society. Observations used PTUSE for data
acquisition, storage, and analysis which was partly funded by the
Max-Planck-Institut fur Radioastronomie (MPIfR).
License: CC-BY-4.0
(End) Patricia Vannier [CDS] 11-Mar-2026